1. Field of the Invention
This invention is in the field of circuits for converting direct current (D.C.) to alternating current (A.C.), and more particularly relates to an inverter having a gate drive circuit for controlling power metal oxide silicon field effect transistors (MOSFETs) of such an inverter.
2. Description of the Prior Art
There are now available MOSFETs that have the capability of handling large electric currents at high voltages. A typical characteristic of MOSFETs is that they have high gate input impedances so that MOSFETs are voltage controlled, and thus require very low gate input power. These characteristics have led to the use of power MOSFETs to control the flow of direct currents through the primary windings of the power transformers of inverters.
MOSFETs, however, have highly non-linear gate capacitance characteristics and wide gate charge tolerances. These less than desirable characteristics require that close attention be given to the design of power MOSFET gate drive circuits, otherwise destructively large currents will flow through the power MOSFETs and the primary windings of the power transformer if both power MOSFETs conduct, i.e., both are on at the same time. Destructively large currents can also result from turning the on-coming MOSFET on too soon; from not turning the on-coming MOSFET on soon enough; or from saturating the core of the power transformer for any reason.